An annotated checklist of Planorbinae (Heterobranchia, Hygrophila, Planorbidae) from northwestern Argentina

The family Planorbidae comprises freshwater gastropods with planispiral, spiral and limpet-shaped shells. Subfamily Planorbinae sensu stricto, has a richness of almost 300 species, with some of the main genera being Biomphalaria Preston, 1910 and Drepanotrema Fischer & Crosse, 1880. Some Biomphalaria species are of concern to human health as they are intermediate hosts of blood flukes in Latin America. In Argentina, the family Planorbidae is represented by 15 species in four genera. In Northern Argentina (NOA region), records of the family are scarce, and most of them are a result of occasional collecting. We provide an updated checklist of Planorbinae in NOA resulting from fieldwork, material in malacological collections, and data in the literature. Nine species occur in the area: four species of Biomphalaria and five of Drepanotrema. Among Biomphalaria species, we recorded Biomphalaria straminea (Dunker, 1848), which is considered a natural host of the blood fluke Schistostoma mansoni Sambon, 1907, for first time in Salta province; the known geographic distribution of B. straminea is extended in the country.

Freshwater gastropods of the western part of the Kola Peninsula and northern Karelia (northern Europe)

The species composition and distribution of freshwater gastropods in the western part of the Kola Peninsula and northern Karelia has been studied. The explored region lies in the far north of Europe and covers several landscape zones: from the northern taiga to the tundra. In sum, seventeen species were found, for each of them the distribution maps and photographs of intraspecific forms of conchological variability are presented. The taxonomic remarks are also given when appropriate. Gyraulus acronicus (Planorbidae) and Ampullacena balthica (Lymnaeidae) are the most common species in the studied region. Two species ( Ampullacena balthica and Galba truncatula ) have been recorded in the Barents Sea islands off the Kola Peninsula. A single non-indigenous species, Physella acuta (Physidae) has been registered in the studied territory. Based on the results of a comparison of the faunas of gastropods from various areas within the whole territory studied and other regions of northern Europe and Western Siberia, it has been shown that the most dramatic reduction in the species composition occurs during the transition from taiga to tundra landscapes.

ON THE ECOLOGY AND SPECIES DIVERSITY OF THE FRESHWATER GASTROPODS OF SPRINGS IN ANDIJAN REGION, UZBEKISTAN

This study examines the species composition, biodiversity, zoogeography, and ecology of freshwater gastropods of 12 springs in Andijan region of Uzbekistan. The study used generally accepted malacological, faunistic, ecological, analytical, and statistical methods. As a result of research in the springs, 14 species of freshwater gastropods belonging to 2 subclasses, 5 families, and 10 genera were recorded. 7 of them are endemic to Central Asia. When indicators of biodiversity of mollusks were analyzed according to the Shannon index, it was found that the highest value was recorded in the springs besides the hills. According to the biotope of distribution and bioecological features, they were divided into cryophilic, phytophilic, pelophilic, and eurybiontic ecological groups. The mollusks, which are common in the springs, were divided into 3 groups according to their faunal similarity. The contribution of the Central Asian and European-Siberian species to the formation of the malacofauna in the springs of the Andijan region was significant.

Current extinction rate in European freshwater gastropods greatly exceeds that of the late Cretaceous mass extinction

The Cretaceous–Paleogene mass extinction event 66 million years ago eradicated three quarters of marine and terrestrial species globally. However, previous studies based on vertebrates suggest that freshwater biota were much less affected. Here we assemble a time series of European freshwater gastropod species occurrences and inferred extinction rates covering the past 200 million years. We find that extinction rates increased by more than one order of magnitude during the Cretaceous–Paleogene mass extinction, which resulted in the extinction of 92.5% of all species. The extinction phase lasted 5.4 million years and was followed by a recovery period of 6.9 million years. However, present extinction rates in European freshwater gastropods are three orders of magnitude higher than even these revised estimates for the Cretaceous–Paleogene mass extinction. Our results indicate that, unless substantial conservation effort is directed to freshwater ecosystems, the present extinction crisis will have a severe impact to freshwater biota for millions of years to come.

The Effectiveness of Filopaludina javanica and Sulcospira testudinaria in Reducing Organic Matter in Catfish (Clarias sp.) Aquaculture Wastewater

HighlightCatfish aquaculture wastewater contains organic matter that exceeds the quality standard of 68.75 mg / L and 72.48 mg / L.Tutut Jawa snail (F. javanica) can reduce organic matter in waste by up to 92%.Susuh Kura snail (S. testudinaria) can reduce organic matter in waste by up to 87%.Catfish aquaculture wastewater treatment with snails only takes 8 hours. Abstract The residual or wastewater from the cultivation process that is discharged directly into common waters can reduce the quality of the waters because it contains a lot of organic material from organism feces and feed residue, so it needs management first. The purpose of this study was to determine the ability of Javanese snails and freshwater gastropods to reduce total organic matter in catfish culture waste. The research method used was the experiment with 2 factor Factorial completely randomized design, namely the measurement time (4, 8, 12, and 16 hours) and the abundance of the Tutut Java snail and freshwater gastropods (100%, 75%, 50%, 25%, and control) with 5 repetitions. Tutut Java snails were taken from the pond at UPR Sumbermina Dau and brought to the laboratory. The results obtained in the treatment with the addition of Tutut Java snail, the total organic matter content decreased at 75% snail density by 90% (from 68.75 mg / L to 5.31 mg / L) at the 12th hour. The treatment with the addition of Freshwater Gastropods at a density of 25%, the total organic matter content decreased by 87% (from 72.48 to 9.35 mg / L) at the 8th hour. Water quality during the study was in a condition that could tolerate the Tutut Java snails and freshwater gastropods. The conclusion is that the addition of Tutut Java snail and / or freshwater gastropods can reduce the total organic matter content to the water quality standard.

The exotic gastropod Clea helena (von dem Busch, 1847) as a predator of freshwater gastropods: a threat to native biota in India?

The carnivorous snail Clea (Anentome) helena (von dem Busch, 1847) (Gastropoda: Nassariidae), commonly called as the “assassin snail” is sold worldwide including India for aesthetics and the ability to kill pest snails in aquaria. Assuming invasion as a fair possibility, the predation potential of C. helena on seven native freshwater snails was assessed. The exotic predator consumed all the native snail species provided in the experiment and prey consumption varied with the prey species identity, the prey density and the prey size class. Future colonization and establishment of C. helena in Indian freshwater ecosystems may reduce the abundance of the native gastropod snails, in absence of suitable intervention.

The current state and specifics of taxonomic structure of trematodes of freshwater molluscs in the Ukrainian Polissia

The paper presents results on the analysis of the taxonomic structure of the trematode fauna of the Ukrainian Polissia. It was found that the trematode fauna of freshwater molluscs in the Ukrainian Polissia is represented by 62 species. We supplemented the species composition of larvae of trematodes in the region with 23 species, 13 of which were first recorded in Ukraine. The results showed that the number of trematode species the definitive hosts of which are fishes have decreased. According to the obtained data, the most abundant trematode species of freshwater molluscs in the Ukrainian Polissia are those of the families Echinostomatidae, Plagiorchiidae, Diplostomidae, and Notocotylidae. The combined analysis of literature and original data revealed that in the basis of the regional trematode fauna of molluscs are species of the families Echinostomatidae (13 species) and Plagiorchiidae (10 species), which make up almost one-third of the total number of trematode larvae detected. A quite large portion of larvae belong to species of the families Notocotylidae (8 species), Strigeidae (7 species), Diplostomidae (5 species), and Haematolechidae (5 species). Most families (Diplodiscidae, Opisthorchiidae, Leucochloridiomorphidae, Prostogonimidae, Cathaemasiidae, Cyclocoelidae, Prohemistomatidae, and others) are represented only by 1–2 species. In freshwater molluscs of the studied region, we have found only 38 % of trematode species recorded in definitive hosts. Species found in vertebrate animals of the region potentially can also occur in intermediate hosts, but most of these species parasitize in birds that could be infected in other areas. When comparing the taxonomic structure of the trematode fauna of the Polissia with other well-studied regions of Ukraine (Northern Pryazovia and Crimea), some specifics were noted between them. In particular, it was found that the most abundant trematode species in the region as well as in the whole of Ukraine are those of the families Echinostomatidae, Plagiorchiidae, Diplostomidae, Notocotylidae, and Strigeidae. The obtained data allow considering that the trematode fauna of freshwater gastropods of the Ukrainian Polissia is an integral part of the Central European fauna of trematodes.

Morphological and molecular characterization of adult hairworms (Phylum Nematomorpha) from Iceland and the Faroe Islands, and documentation of their non-adult stages and hosts

No species of freshwater Nematomorpha have been described from Iceland, but they have been identified anecdotally. Recent surveys in Iceland using freshwater gastropods as biodiversity indicators resulted in the collection of adult free-living hairworms and their non-adult stages including cysts in snail paratenic hosts and juvenile worms in ground beetle definitive hosts. Additionally, specimens acquired from the Icelandic Institute of Natural History indicate nematomorphs are common in Iceland. A single specimen from the Faroe Islands National Museum represents a new species record. Our morphological and molecular characterization indicated all the samples belong to the species Gordionus wolterstorffii, a common nematomorph found throughout Europe. Also, we provide the first descriptions of the cyst stage for the genus Gordionus. Molecular phylogenetic analysis based on 10 species of Gordionus and one species of the closely related genus Parachordodes indicates that Gordionus is not monophyletic. Combining our morphological and phylogenetic investigations, we discuss the lack of clarity in diagnostic morphological characters and the need for additional global collections to clarify the taxonomy of Gordionus.